A Minnesota Homeowner’s Guide to Ice Dams

Winter weather comes with many potential threats to the safety, warmth, and structural integrity of your home, from gale force winds to heavy snowfall. One of the most common cold weather hazards is the ice dam.

Ice dams are most likely to form when the temperature fluctuates. So while you may breathe a sigh of relief to have a break from Minnesota's well below freezing temperatures for a few days, higher temperatures do not negate the risks to your home. Ice dams are especially common in the late winter and early spring when the weather may warm up and then drop below freezing again unexpectedly.

In this blog, we provide the information you need to protect your home from ice dams and the damage they cause.

How Ice Dams Form

As the name suggests, an ice dam consists of a large section of ice near the edge of a roof that effectively dams precipitation and runoff. Ice dams occur when snow on the roof melts but refreezes before it flows off of the roof. Often, the snow melts due to warm attic temperatures at the highest point of the roof and freezes as the water reaches the colder edge of the roof.

Higher attic temperatures can happen due to inadequate insulation or ventilation. When you have poor attic insulation, the heat from your home may rise right into and out of the attic, creating warm spots on the roof.

Poor attic ventilation, on the other hand, prevents heat from escaping the attic space, raising the temperature much higher than usual. This lack of air circulation can also create warm areas on the roof and melt snow.

Ice dams may build up over time in layers every time conditions are right for snow to melt on the upper roof and freeze near the edge.

Ice Dam Prevention

The only way to prevent ice dams is to ensure that rooftop temperatures never rise above 32°F when there's snow on the roof. Take these steps to minimize the risk of an ice dam forming on your roof:

If your home has a history of ice dams, consult with a contractor during warmer weather to reduce the risk of future damage.

Signs of an Ice Dam

It's important to identify existing ice dams as quickly as possible. Look for the following signs.

Hot Spots on the Roof

As mentioned in the first section, ice dams often form when the roof heats up in certain areas enough to melt the snow. These sections are called hot spots and they may be visible from the ground.

Assess your roof, preferably while temperatures are below freezing. If you notice large sections of clear roof, your home may be at risk for an ice dam.

Interior Leaks and Water Damage

One of the biggest dangers of ice dams is that they trap water where your roof is more vulnerable to leaks. If you have a large enough ice dam, you may start to notice water intrusion inside your home.

Look for dripping leaks from the ceiling, water seeping in around window and door frames, water damage in your attic, and stains where the outermost walls meet the ceiling.

Oversized or Misshapen Icicles

Many homeowners mistakenly believe that icicles on the eaves of their roofs indicate the presence of an ice dam. While icicles and ice dams can appear simultaneously, the two ice formations are not always related.

If your icicles are particularly large, are attached to your gutters rather than your roof, or are attached to an ice formation that looks like a wave flowing over the edge of the roof, you likely have an ice dam.

If you notice one or more of these signs, assume that your roof has some form of ice dam on it.

Ice Dam Remediation

When dealing with an ice dam, put your safety first. If you can easily access your roof and you have the necessary safety equipment, you can attempt to remove the dam by applying ice melt to the affected area.

If the ice dam does not respond to this treatment or you cannot confidently access your roof, schedule professional remediation instead. A professional may use heated air, steam, or industrial ice melt to remove the dam. The technician will ensure that water drains off of your roof appropriately during the process and that measures are put in place to reduce the risk of ice dam formation for the rest of the winter.

Use the guidelines below to ensure that your home stays cozy and warm until the last of the snow melts away.